Answer:
22.7551745473%
Explanation:
I could be very wrong but to find the percentage of change you have to divide the increase by the original number, and then multiply it by 100.
20851820-16986510=3865310
3865310/16986510=0.22755174547
0.22755174547*100=22.755174547
This answer can then be rounded up to 23%